Indeed I'm using earmaster 5 with a delay of 225ms (so that now there's no awkward dekay in the rhythm exercises). Should I change anything?

Yes. And sometimes the sounds of my tapping and of the metronome disappear for 1-2 seconds.
Actually the recording that I posted was done through audacity so the problem is prior to outputing the sound.

Thanks for your answer.
It turns out that my driver is marked as updated and the Realtek HD manager is already set for 16Bit/48kHz.
I also try to train without an opened browser etc. Nothing changed.

It's an on board simple card, I saw the name Realtek.
I guess this isn't optimal but can I do something to improve the situation apart from buying an external soundcard?

Actually I train just in Rhythm Reading. And I hear this every day, once in a while.

I've already fixed the delay through the settings but when I tap my reading, sometimes the sound of my tapping cracks or goes away. The metronom sound is still Ok. Anyone know what can I do? My desktop is 3.3GHZ and 4GB. Edit: Maybe there's a way to give my input otherwise than through a keyboard or...